1. Field of the Invention
This invention relates to surgical suction devices for the removal of surgical debris.
2. Description of the Prior Art
Suction devices are used during surgical procedures to remove fluids and debris from the operating field. Various designs have been proposed for these devices. Typically, such devices include a tip which is inserted into the surgical field and a means, usually a conduit or a tube, for connecting the tip to a vacuum source. However, these known devices have proven unsatisfactory in some aspect.
The designer of a surgical suction device must consider various factors. The device must be easy and convenient to use and must minimize the amount of disruption to the surgeon. The time required to clear the field may impact both the total length of the procedure and the ability of the surgeon to identify problems within the field and complete the procedure. The length of the procedure affects both the surgeon and the patient. Procedures lengthened unnecessarily are unduly tiring to the surgeon and expose the patient to anesthesia for a prolonged period. Therefore, the time required to use the device must be minimized. Ease of use contributes to minimization of the time required to complete the surgery and facilitates operation of the device by less trained personnel.
The device must also minimize the disruption of the patient's tissues. Aspects of disruption which must be considered include the size of the incision required and the trauma to tissue should it be aspirated into the device. The suction device should not require that the operating field be adjusted to accommodate it. Further, it is inevitable that tissue will be exposed to suction through inadvertence or inability to properly clear the field without impinging upon tissue. Therefore, the device should minimize tissue trauma by minimizing both the space required to use it and the tendency to injure aspirated tissue.
Further, the suction device must clear the field effectively. Typically, blood and other fluids, such as saline irrigating fluid and the like, will be present in the operating field. Solids and semi-solids such as coagulated blood, bone chips, excised tissue particles, and the like will also be present. All these materials must be removed from the operating field without extraordinary effort. The device must continue to operate effectively in the presence of these materials without requiring repeated and prolonged interruptions to unblock the device.
Various designs have been proposed to satisfy the above-described factors. For example, devices which control the amount of suction by moving the suction source relative to perforations in the tip are common. See, for example, U.S. Pat. Nos. 3,426,759 and 4,487,600. Some of these devices take advantage of relative motion to attempt to shear blockages of the suction tip, as in U.S. Pat. Nos. 3,308,825 and 4,400,168. However, these designs are, for the most part, not commercially accepted because they are unduly difficult to operate. For example, the design in U.S. Pat. No. 3,308,825 requires that a locknut be loosened to allow the suction tube to slide within the suction tip and adjust the number of holes exposed to suction. The locknut must then be tightened to fix the location of the suction tube in relation to the suction tip. U.S. Pat. No. 4,400,168 requires that the thumb of the user's hand be utilized when varying the number of suction holes exposed and when shearing off blockages. The former procedure is complex while the latter requires a great deal of concentration and manual dexterity. Further, shearing apparatus typically require metal construction, thereby raising costs. Therefore, these designs are less than satisfactory.
Other devices vary the amount of suction available by sliding a suction tube within a perforated tip, as in U.S. Pat. No. 4,487,600, or by providing an opening between the vacuum source and the suction tip, as in German O.S. No. 1,491,755. However, both designs are flawed, the latter being unwieldy to operate, the former tending to clog and make the suction too strong when the suction is directed at only the holes closest to the tip.
Other designs, such as U.S. Pat. No. 3,963,028, while simple to manufacture and operate, are prone to clogging as the tip impinges upon tissue because the holes in the suction tip are relatively closely spaced. Designs which provide for atraumatic withdrawal of blood, such as U.S. Pat. No. 3,623,483, do not provide for adjustment of suction strength. Further, this design requires displacement of tissue within the field and a pool of blood from which to draw. Therefore, it is difficult to use such a design to completely dry a field.
Finally, other designers have circulated anti-coagulant in the tip. The anti-coagulant delivery device described in U.S. Pat. No. 3,955,573 is intended for use in autologous blood transfusion. Therein, anti-coagulant is delivered within a bulbous suction tip designed to thoroughly mix the anti-coagulant with the blood being aspirated. Therefore, the clotting tendency is almost immediately suppressed, thereby preventing clotting and blockages within the device. U.S. Pat. No. 2,804,075 discloses an anti-coagulant delivery system and teaches that when the suction holes become blocked, anti-coagulant accumulates within the tip and usually clears the blocked holes. Further, bone chips are said not be able to block the aspirator because the holes in the suction tip are smaller than the suction tube diameter. However, this does not explain why a bone chip might not block the suction tip itself nor how a blockage which is not affected by anti-coagulant, such as a flat globule or a piece of excised tissue, would be removed.
None of these devices have proven to be satisfactory. Therefore, it is an object of this invention to provide a surgical suction device which is convenient to use, clog resistant, efficient, and able to quickly clear an operating field of surgical debris while minimizing damage to tissue. It is a further object of this invention to provide a surgical suction device wherein the suction ports are disposed in a fashion which ensures that at least some of the suction ports will remain unclogged.